Current fuel injectors include a tip member carried in a jacket or case. A barrel is threaded into or otherwise secured to an upper end of the case. A check along with other components are disposed within the case and the check is movable into engagement with a check seat formed on an inside surface of the tip member. In the past, a two-piece tip member was utilized wherein a lower member containing the seat and injection orifices was mounted in an elongate upper member through which the check extended.
Recently, fuel injector designs have been developed wherein improved response times are obtained through the use of a valve which directs high pressure fuel onto the top of the check. The application of the high pressure fuel to the top of the check results in very high check velocities. While these high check velocities enable a quick end of injection, which is beneficial from an emissions standpoint, the momentum built up by the check is in excess of the design limits of the two piece tip member of prior fuel injector designs. That is, if the two piece design were utilized, the lower member could be pushed out of contact with the elongate upper member thereby leading to damage not only to the injector but possibly engine components. Accordingly, a single or integral tip design must be utilized. However, tip failures have occurred, indicating the difficulty of designing a tip member which will withstand simultaneous check impact and the high pressures that are encountered in current fuel injectors.